Vehicles have generally been mounted with audible warning devices for generating a warning to another vehicle, a pedestrian, or the like. A volume level of the warning have generally been set to a singular, set level so as to satisfy industry specifications for causing the audible warning to be recognizable by others vehicles; however, one response may not suit all vehicle environments. For example, pedestrians and/or bicyclists may feel that the volume level is excessively high in some cases, causing them to be unnecessarily startled.
Some audible warning devices may include a loud volume level for other vehicles, and another, softer volume level for pedestrians and/or bicyclists (such as a whistle or other sound).
Also, because a hybrid vehicle may operate at a quiet level, as compared with a conventional combustion-engine vehicle, it may be necessary to make the vehicle's presence recognizable by another vehicle or pedestrians around the vehicle, but without the attention, or startling effect, that may be drawn by a convention, high-volume level audible warning. Also, conventional audible warning systems have either required excessive vehicle operator involvement, or distraction, to select and sound the appropriate audible warning.